To assign a new batch to existing learners in the courses, follow the below mentioned steps:
Select the Courses/Batches section from the home screen of the particular organization.
Select the particular course.
Click on the Participants option.
Select the three vertical dots against the name of the person whom you want to assign a batch and click on the Assign Batch option.
Select the desired batch from the list of batches and click on the Assign option to assign the batch.